Field of the Invention
The present invention relates to a semiconductor device assessment apparatus, and more specifically to a semiconductor device assessment apparatus capable of positionally detecting a semiconductor device.
Description of the Background Art
In a semiconductor device production process, semiconductor devices formed on a semiconductor substrate may have their electrical characteristics assessed before the semiconductor substrate is diced into individual semiconductor devices. In this case, the semiconductor device is assessed via an assessment apparatus generally including a stage (or a holding unit) to hold the semiconductor substrate during an assessment and a probe electrically connected to a pad of the semiconductor device formed on the semiconductor substrate. In the assessment, the semiconductor substrate is previously disposed with its center positioned at a reference position on the stage. This allows a plurality of semiconductor devices formed on the semiconductor substrate to be registered with respect to the stage all at once, and once they have been registered, the probe and the stage can be relatively moved to assess each semiconductor device individually. The semiconductor substrate may have its center position matched to the reference position on the stage by a method utilizing a peripheral edge of the semiconductor substrate.
Japanese Patent Laying-Open No. 6-302676 discloses an apparatus to inspect a wafer for foreign matters. More specifically, a wafer is placed on a table and a peripheral portion of the wafer that projects radially outer than the table is exposed to incident light, which is reflected by a mirror that is provided under the wafer adjacent to the peripheral portion's back surface to obtain an image of and near the wafer.